The Murphy Builders Site

Al,

Our flying club bought a Mattituck PMA engine about a year ago now and had the same failure and damage within the first 50 hours. Wonder if the 2 companies buy their bearings for the vacuum pump drive shaft from the same supplier?

Terry

-- "Alan Hepburn" <ahepburn@renc.igs.net> wrote:
G-FGAH is now airborne again. The cause of the engine failure was a
seized bearing on the vacuum pump drive shaft, which knocked two teeth
of the camshaft drive gear, and also damaged the keyway on the
crankshaft. Aerosport power fixed everything, and paid the freight
both ways, but it still put a major delay in the flight test program.

- cut text -

Al Hepburn





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Interesting. Aerosport Power use Superior parts, which of course are
extremely common. Seems to me from the ads I've seen that Mattituck also
uses them. As far as I know, the non-certified engines are built from PMA
parts. They did indicate that there had been some indication of similar
failures, and that the suspected cause was low clearance on the bearing (0.5
thou, vs 1.5 thou spec).

I'm surprised that there hasn't been an SDR filed if the problem has
occurred on several occasions. If there was, I imagine the s**t would hit
the fan.

At what stage in flight did yours happen? I was forutunate to be firmly on
the ground.

Did a climb to 5,500' today, with a ground temperature of 33C, and never saw
above 100C on the oil, and 237C on the CHT, so I'm satisfied that the cowl
mods did the trick.

Al

----- Original Message -----
From: <tlmcclary@juno.com>
To: <rebel-builders@dcsol.com>
Sent: Monday, August 08, 2005 11:30 AM
Subject: C-FGAH engine

Al,

Our flying club bought a Mattituck PMA engine about a year ago now and had

the same failure and damage within the first 50 hours. Wonder if the 2
companies buy their bearings for the vacuum pump drive shaft from the same
supplier?

Terry

-- "Alan Hepburn" <ahepburn@renc.igs.net> wrote:
G-FGAH is now airborne again. The cause of the engine failure was a
seized bearing on the vacuum pump drive shaft, which knocked two teeth
of the camshaft drive gear, and also damaged the keyway on the
crankshaft. Aerosport power fixed everything, and paid the freight
both ways, but it still put a major delay in the flight test program.

- cut text -

Al Hepburn





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